<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
          #cls{
              text-align: center;
              margin-top: 100px;
          }
          img{border-radius: 50%;
          cursor: pointer;
          transform: scale(1);
              -moz-transform: scale(1);
              -webkit-transform: scale(1);
              -o-transform: scale(1);
          transition: all .5s;}
          img:hover{
              transform: scale(1.1);
              transition: all .5s;
              -webkit-transition: all .5s;
          }
    </style>
</head>
<body>
  <div id="cls">
       <img src="img/001.jpg" alt="头像">
  </div>
</body>
</html>